Venting-door for circuit-breaker casings.



F. 5. CASE.

VENTING DOOR FO R CIRCUIT BREAKER CASINGS.

APPUCATiON FILED AUG-I1, 19M.

1, 181 ,736. Patmted May 2, 1910.

WITNESSES! INVENTURIV m\f ,g g g FRANK E. EASE,

yflzzw- WQM H15 ATTU NEY.

25 for insulating the interior of the box.

40 with the switch contacts.

UNITED STATES PATENT OFFICE.

' FRANK E. CASE. OF SCHENECTADY, NEW YORK, ASSIGNOR- TO GENERAL ELECTRICCOMPANY. A CORPORATION OF NEW YORK.

Specification of- Letters Patent.

Patented May 2, 1916.

Application filed August 11, 1914. Serial No. 856.255.

New York. have invented certain new and useful Improvements inVenting-Doors for Circuit-Breaker Casings, of which the following is aspecification.

This invention relates to electromagnetic switches for controllingelectric circuits,

especially those carrying heavy currents. The invention is applicable toany such device where the breaking of the circuit is "attended by theformation of an are between the switch contacts as they separate. A blowout magnet is usually provided to extinguish the arc and a chute todirect the flame and gases away from the vicinity of the switchmechanism.- It: is also customary to inclose these switches, especiallycircuit breakers and contactors, in protecting casings. But it is foundthat in order to successfully open a heavy circuit in a completelyclosed box, extraordinary precautionshave to be taken The pressure ofthe gas produced in opening the circuit is liable to divert the currentand cause it to jump between points at a considerable distance from themain contacts,

and the object of the present invention is to eliminate this trouble. Ithas been found that a hinged-door in the casing, closed by pressure ofthe'gas in the box is sufficient to move it, so that it does not whollyremove the trouble. I have therefore provided a door hinged at the topand having an arm acting as the armature of a coil in series WVhen thecurrent becomes excessive, the door will be pulled open just before theare at the contacts has attained sufiicient magnitude'to cause anincrease in gaseous pressure, thereby afi'ording ample opportunity forthe arc to be projected through the opening and reducing the tendencyfor it to take some abnormal course.

In the accompanying drawing, Figure 1 is a cross section of a circuitbreaker or concontacts open.

The circuit breaker illustrated 1s a stand- 65' ard form of contactor,having a solenoid 1,

a movable core 2 therefor. a main switch lever 3 hinged at i and pivotedto said core at 5, a' nain contact brush (3 on said lever cooperatingwith a stationary contact I, a secondary contact 8 cooperating with thecontact T and carried on an auxiliary lever 9 pivoted at 10 to the mainlever 3 and having a slot 11 to permit its rear end to play past thepivot 5 of the core. a spring 12 bearing on the tail of the lever 9 togive the second ary contacts a yielding and wiping action, an arc chute13 inclosing the contacts. and a blow out magnet 14. The contactor isinclosed in a box or casing 15 of any suitable construction. In the sideof this box adjacent to the arc chute is an opening, closed by a lightdoor 16 hinged at its top so as to open outwardly. An arm 17 on the doorextends above the hinge joint and carries an iron piece 18 which acts asan armature for the coil 19 in series with the conductor '20, whosecircuit is controlled by the switch con tacts.

the coil 19 it attracts the armaturelS and thereby swings open the door'16. as indicated in dotted lines in Fig. 1. This aiiords an outlet forthe flame and gas which follow the breaking of the circuit at the switchcontacts, and thus prevents any injurious accumulation of pressure inthe box.

In accordance with the provisions of the patent statutes, I havedescribed the principle of operation of my invention, together with theapparatus which I now consider to represent the best embodiment thereof;but I desire to have it understood that the apparatus shown is onlyillustrative, and that the invention can be carried out by other means.

What I claim as new and desire to secure by'Letters Patent of the UnitedStates, is

1. The combination with an electromagnetic switch and a casing inclosingthe same, of a door in said casing adjacent the switch contacts. andmeans controlled by the current flowing through the said switch con-.,tacts for opening said door.

2. The combination with an electromagnetic switch and a casing inclosingthe same, of a door in said casing. and means for automatically openingsaid door upon an abnormal rise of current.

3. The combination with an electromagnetic switch having a casinginclosing the \Vhen an abnormal current flows through saine ot' a doorin said casing, and a series coil for opening said door.

r. The combination with an electromagnetic switch and a casing inciosingthe same, of a door in said casing an armature on said door, and aseries coil cooperating with said armature to open the door.

5. The combination with an electromagnetic switch and aeasing inciosingthe same, of a door in said casing hinged at the top, an armatureextending above the hinged joint and a series coil adjacent to saidarmature.

6. The combination with an electromagnetic switch having an armature, ofa casing for said switch having a door adjacent to said switch, andmeans for opening said door just before a dangerous rise of pressure insaid casing due to arcing between the switch QontaCU-z.

T; The combination with an netie switeh and a casing inciosing he of adoor in said casing: a coil in selie the contacts of said switch andmean: by the door opened by said (:nii when current through the contactsand rho rises to a point where the innsrruption the circuit at thecontacts would come dangerous pressure in the casing.

In witness whereof. I have ilrl'ttiifiw set no in hand this 10th day ofAugust 19H.

FRAX K ii. (A 5K.

'itnesses HELEN ()Rrono. BENJAMIN B. Hui.

